Network nodes can use forwarding tables to forward packets towards their destination. Network nodes may take form in one or more routers, one or more bridges, one or more switches, one or more servers, or any other suitable communications processing device. A packet is a formatted unit of data that typically contains control information and payload data. Control information may include: source and destination IP addresses, error detection codes like checksums, sequencing information, etc. Control information is typically found in packet headers and trailers, with payload data in between.
Packet forwarding requires a decision process that, while simple in concept, can be complex in implementation. Since packet forwarding decisions are handled by network nodes, the time needed to make packet forwarding decisions can become a major limiting factor in overall network performance.
Multiprotocol Label Switching (MPLS) is one packet forwarding mechanism employed by network nodes. MPLS Nodes can make packet forwarding decisions based on Label Distribution Protocol (LDP) labels (hereinafter labels). Packet forwarding based on labels stands in stark contrast to traditional Internet Protocol (IP) routing in which packet forwarding decisions are based on IP addresses contained within packets.